clc;
syms x y; 
f=(x*y/(x^2+y^2))^(x^2); 
L1=limit(limit(f,x,inf),y,inf), 
L2=limit(limit(f,y,inf),x,inf), 
L3=limit(limit(f,x,y^2),y,inf), 
L4=limit(limit(f,y,x^2),x,inf)